GLASIALGEOLOGI

The superficial deposits occurring within the area of this map-sheet are classified according to their genesis and described. Based on glacial striae and till stratigraphy 3-4 regional and one (youngest) local icemovement directions are reconstructed. During deglaciation the meltwater was ice-directed. Three phases in the deglaciation are distinguished on the basis of changing meltwater drainage routes.

The superficial deposits occurring within the map-sheet are classified and described according to their genesis. The ice-marginal lines - Repparfjord- trinnet and the younger Hovedtrinnet - are reconstructed and it is suggested that these events belong to the Older Dryas and Younger Dryas chronozones, respectively. Till and weathering material (blockfield) dominate the superficial material. Glaciofluvial and fluvial deposits occur mostly in the main valley, Repparfjorden. Several well-defined meltwater channels are present in the Skaidi area. These channels might indicate that meltwater runoff increased when the front of the glacier reached this point of the valley. Seismic profiles have been used to calculate the volume of some of the glaciofluvial deposits. Various geotechnical tests have been carried out on some of these sediments in order to classify them for technical purposes.

The superficial deposits within the map-sheet Nordatugu, southeastern Norway, are classified and described. Most of the mountainous areas are dominated by exposed bedrock or a thin and discontinuous cover of till. In the main valleys, below the marine limit (c. 150 m a.s.l.) fine-grained marine sediments dominate. Large glaciofluvial deposits exist in the valley of Saua, north of Nordsjø. Chemical analyses have been carried out on samples from the superficial deposits. Ice movements and the course of deglaciation have been reconstructed. The oldest ice movement was towards the south, later turning towards SE and ESE. During the deglaciation of the mapped are, there were three glacial events marking advances or halts of the ice-front. The Geitryggen event is correlated with the deposition of the Ski Moraine in the Osdlofjord region and dated to c. 10 000 years B.P. Most of the Nordagutu area was still covered by ice at this time. The younger Akkerhaugen and Nordagutu events have been dated to c. 9800-9750 years B.P., respectively. Short accounts are given on shorelines, shorelevel displacement and pollen analyses. The potential for different utilization of the superficial deposits is also briefly discussed.

Forkortet. Jæren in southwestern Norway is covered with a sheet of Late Weichselian glacial deposits which in places overlies rather thick units of older glacial and marine deposit. Younger Late Weichselian and Holocene marine sediments, eolian sand and peat cover parts of the Late Weichselian sheet. The distribu- tion of the surficial deposits was mapped, and numerous analyses of grain size, fabric, clastic roundness and pebble counts were used to characterize the depositional environments. On the basis of lithostratigraphical, bio- stratigraphical and cronostratigraphical studies, including datings by differ- ent methods, a stratigraphical model is presented for the Late Weichselian and older deposits. The model is preliminary, since the dating and correlation of deposits older than 25 000-30 000 years B.P. remain uncertain. All units in the model are mentioned in stratigraphical order.

Marginal moraines have been mapped and the course of deglaciation reconstructed
supported by studies on terraces and shorelines and by radiocarbon datings.
The following glacial events have been recognised:
1. Davik stadial, age unknown, glacier front somewhere in the outher fjord area
2. Vardehaug stadial, of early Younger Dryas age (10.700-10.600 B.P.), glacier
front at Naustdal, Eidsfjorden 3. No stadial, later half of Younger Dryas,
glacier front at Nor (Nordfjordeid), Anda and Rygg. The Nor stadial is by far
the most marked late glacier event in Nordfjord, both with regard to the thick-
ness of the deposits as well as to their distribution and continuity, and is
correlated with the main Younger Dryas readvance in Norway. This stadial is
completely reconstructed, and a paleogeographic map is presented.
4. Vinsrygg stadial, early Pre-Boreal, characterized by active glaciers,
glacier front in the fjord outside Stryn. 5. Eide stadial, of Pre-Boreal age
(> 9400 years B.P.), front of valley glaciers near the heads of the innermost
fjord branches. Local moraines, primarily in front of cirques, are numerous
and frequently reflected several stadials, although Nor moraines dominate.
The Nor raised marine shoreline is a prominent feature in greater parts of the
area, and an isobase map for Nordfjord and Sunnmøre is presented.
The Younger Dryas lowering of snow lines and glaciation limits is estimated at
approximately 450 m

Som ledd i prosjekteringen av Mauranger Kraftanlegg inngår en tunnel under Folgefonni. NGU fikk i oppdrag å utføre seismiske målinger for å bestemme istykkelsen langs profilet, d.v.s. over en lengde av ca. 6 km. Det ble utført målinger etter vanlig seismisk refraksjonsmetode. Høyden langs profilet varierte mellom ca. 1150 m.o.h. og ca. 1570 m.o.h. Snødekket varierte anslagsvis mellom 5 og 8 m. Det ble registrert istykkelser på opp til ca. 280 meter.